Magnetic recording apparatus and method therefor, and magnetic recording and reproduction apparatus and method therefor

ABSTRACT

Recording data having a data format corresponding to a predetermined digital recording method is generated and the recording data of two tracks in the digital recording method is continuously recorded in one track on magnetic tape. In addition, in this case, control data indicating the arrangement of the frequencies of pilot signals in each track on the magnetic tape is inverted at an interval of two frames in the NTSC system and of one frame in the PAL system and placed in the recording data.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to magnetic recording apparatuses andmethods therefor, and magnetic recording and reproduction apparatusesand methods therefor, and for example, to those suited to digital videocameras.

2. Description of the Related Art

As a recording method for digital video tape recorders, the DigitalVideo (DV) method (IEC 61834, helical scan digital video tape cassetterecording system using 6.35 mm magnetic tape for consumers (525/60,625/50, 1125/60, and 1250/50 systems)) has been conventionally used.Video cameras and installation-type video tape recorders employing theDV method have been commercially available these years.

In the DV method, magnetic tape (hereinafter called DV tape) to be usedhas a width of 6.35 mm (=one fourth inch), which is narrower than thetape width (8 mm) of magnetic tape (hereinafter called 8-mm tape) to beused by the Analog 8-mm method (IEC 60843, helical scan video tapecassette recording system using 8 mm magnetic tape for consumers), whichhas been widely used as a recording method for conventional analog videotape recorders.

Since the DV method compresses video and audio signals to be recordedand uses an increased recording density with a narrower tape width,high-quality recording is implemented for a long period of time.

Although the DV method is not compatible with the Analog 8-mm method, ifvideo and audio signals conforming to the DV-method data format can berecorded on 8-mm tape, which is wider than the DV tape, video and soundcan be recorded for a long period of time with high quality. Inaddition, current resources for 8-mm tape such as production facilitiesand related components can be effectively used for cases in which the DVmethod is employed as well as for cases in which the Analog 8-mm methodis employed.

When a function for reproducing analog 8-mm tape is further provided,analog 8-mm libraries and other resources can be enjoyed.

SUMMARY OF THE INVENTION

Accordingly, it is an object of the present invention to provide amagnetic recording apparatus and a method therefor, and a magneticrecording and reproduction apparatus and a method therefor which allow avideo signal to be recorded with high quality for a long period of time.

The foregoing object is achieved in one aspect of the present inventionthrough the provision of a magnetic recording apparatus includingrecording-data generation means for applying predetermined signalprocessing which includes processing for adding a pilot signal fortracking control, to a video signal to generate recording data having adata format corresponding to a predetermined digital recording method;and recording means for sequentially recording the recording datagenerated by the recording-data generation means, of two tracks in thedigital recording method continuously in one track on magnetic tape,wherein the recording-data generation means places in the recording dataone-bit control data indicating the arrangement of the frequencies ofpilot signals in tracks on the magnetic tape, the one-bit control databeing inverted at an interval of two frames in the NTSC system and ofone frame in the PAL system.

In the magnetic recording apparatus, since recording data having a dataformat corresponding to a digital recording method, of two tracks in thedigital recording method is continuously recorded in one track onmagnetic tape, a video signal can be recorded with high quality for along period of time. In addition, when the next scene is recorded onmagnetic tape where recording data has been recorded; according to thecontrol data included in the recording data, the frequencies of pilotsignals to be added to recording data to be newly recorded for the nextscene are easily determined such that the arrangement of the frequenciesof the pilot signals which have been recorded in tracks where therecording data has been recorded is followed by a predetermined pattern.

The foregoing object is achieved in another aspect of the presentinvention through the provision of a magnetic recording method includinga first step for applying predetermined signal processing which includesprocessing for adding a pilot signal for tracking control, to a videosignal to generate recording data having a data format corresponding toa predetermined digital recording method; and a second step forsequentially recording the generated recording data of two tracks in thedigital recording method continuously in one track on magnetic tape,wherein, in the first step, one-bit control data indicating thearrangement of the frequencies of pilot signals in tracks on themagnetic tape, the one-bit control data being inverted at an interval oftwo frames in the NTSC system and of one frame in the PAL system, isplaced in the recording data.

According to the magnetic recording method, since recording data havinga data format corresponding to a digital recording method, of two tracksin the digital recording method is continuously recorded in one track onmagnetic tape, a video signal can be recorded with high quality for along period of time. In addition, when the next scene is recorded onmagnetic tape where recording data has been recorded; according to thecontrol data included in the recording data, the frequencies of pilotsignals to be added to recording data to be newly recorded for the nextscene are easily determined such that the arrangement of the frequenciesof the pilot signals which have been recorded in tracks where therecording data has been recorded is followed by a predetermined pattern.

The foregoing object is achieved in yet another aspect of the presentinvention through the provision of a magnetic recording and reproductionapparatus including recording-data generation means for applyingpredetermined signal recording processing which includes processing foradding a pilot signal for tracking control, to a video signal togenerate recording data having a data format corresponding to apredetermined digital recording method; and recording means forsequentially recording the recording data generated by therecording-data generation means, of two tracks in the digital recordingmethod continuously in one track on magnetic tape, wherein therecording-data generation means places in the recording data one-bitcontrol data indicating the arrangement of the frequencies of pilotsignals in tracks on the magnetic tape, the one-bit control data beinginverted at an interval of two frames in the NTSC system and of oneframe in the PAL system.

In the magnetic recording and reproduction apparatus, since recordingdata having a data format corresponding to a digital recording method,of two tracks in the digital recording method is continuously recordedin one track on magnetic tape, a video signal can be recorded with highquality for a long period of time. In addition, when the next scene isrecorded on magnetic tape where recording data has been recorded;according to the control data included in the recording data, thefrequencies of pilot signals to be added to recording data to be newlyrecorded for the next scene are easily determined such that thearrangement of the frequencies of the pilot signals which have beenrecorded in tracks where the recording data has been recorded isfollowed by a predetermined pattern.

The foregoing object is achieved in still another aspect of the presentinvention through the provision of a magnetic recording and reproductionmethod including a first step for applying predetermined signalrecording processing which includes processing for adding a pilot signalfor tracking control, to a video signal to generate recording datahaving a data format corresponding to a predetermined digital recordingmethod; and a second step for sequentially recording the generatedrecording data of two tracks in the digital recording methodcontinuously in one track on magnetic tape, wherein, in the first step,one-bit control data indicating the arrangement of the frequencies ofpilot signals in tracks on the magnetic tape, the one-bit control databeing inverted at an interval of two frames in the NTSC system and ofone frame in the PAL system, is placed in the recording data.

According to the magnetic recording and reproduction method, sincerecording data having a data format corresponding to a digital recordingmethod, of two tracks in the digital recording method is continuouslyrecorded in one track on magnetic tape, a video signal can be recordedwith high quality for a long period of time. In addition, when the nextscene is recorded on magnetic tape where recording data has beenrecorded; according to the control data included in the recording data,the frequencies of pilot signals to be added to recording data to benewly recorded for the next scene are easily determined such that thearrangement of the frequencies of the pilot signals which have beenrecorded in tracks where the recording data has been recorded isfollowed by a predetermined pattern.

As described above, according to the present invention, since recordingdata having a data format corresponding to a predetermined digitalrecording method is generated and the recording data of two tracks inthe digital recording method is continuously recorded in one track onmagnetic tape, a video signal can be recorded with high quality for along period of time. In addition, in this case, since control dataindicating the arrangement of the frequencies of pilot signals in trackson the magnetic tape is inverted at an interval of two frames in theNTSC system and of one frame in the PAL system and placed in recordingdata, the frequencies of pilot signals to be added to recording data tobe newly recorded for the next scene are easily determined according tothe control data such that tracking is maintained even at the boundaryof a recorded video signal and a video signal for the next scene.Therefore, a magnetic recording apparatus and a method therefor, and amagnetic recording and reproduction apparatus and a method therefor,which allow a circuit structure and a program to be simplified areimplemented.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an outlined view showing recording conditions in the DigitalVideo (DV) method.

FIG. 2 is a view showing a recording-data format in the DV method.

FIG. 3 is an outlined view showing recording conditions in a digital8-mm method.

FIG. 4A is an outlined view showing an automatic track finding (ATF)format used for the NTSC system in the DV method.

FIG. 4B is an outlined view showing an ATF format used for the NTSCsystem in the digital 8-mm method.

FIG. 5A is an outlined view showing an ATF format used for the PALsystem in the DV method.

FIG. 5B is an outlined view showing an ATF format used for the PALsystem in the digital 8-mm method.

FIG. 6 is a timing chart showing the relationship between thefrequencies of pilot signals, and DV track numbers and first and secondpilot-frame signals in the NTSC system.

FIG. 7 is a timing chart showing the relationship between thefrequencies of pilot signals, and DV track numbers and first and secondpilot-frame signals in the PAL system.

FIG. 8 is a block diagram of a digital video camera according to anembodiment of the present invention.

FIG. 9 is a timing chart showing the relationship between thefrequencies of pilot signals, and DV track numbers and first and secondpilot-frame signals in the NTSC system in the digital video camera shownin FIG. 8.

FIG. 10 is a timing chart showing the relationship between thefrequencies of pilot signals, and DV track numbers and first and secondpilot-frame signals in the PAL system in the digital video camera shownin FIG. 8.

DESCRIPTION OF THE PREFERRED EMBODIMENT

An embodiment of the present invention will be described below byreferring to the drawings.

(1) Recording Method in the Present Embodiment

A recording method to which the present invention is applied will bedescribed below by comparing it with the conventional DV method. Therecording method to which the present invention is applied is a methodfor recording video and audio signals (hereinafter called DV data)conforming to the DV-method data format into 8-mm tape, and is called adigital 8-mm method in the following description.

In the DV method, as shown in FIG. 1, a rotating drum 2 having adiameter of 21.7 mm is rotated in a direction indicated by “a₁” at arotating speed of 9000/1.001 rpm in the NTSC system and of 9000 rmp inthe PAL system against DV tape 1 having a tape width of 6.35 mm torecord DV data.

In this case, two magnetic heads 3A and 3B having different azimuthangles are mounted at positions 180 degrees apart on the rotating drum2. Therefore, the two magnetic heads 3A and 3B alternately scan the DVtape 1 which runs in a direction indicated by “b₁” at a predeterminedangle. As a result, tracks 4 are sequentially formed at angles in thelongitudinal direction of the DV tape 1 as shown in FIG. 1.

In the DV method, when tracks 4 formed by one of the magnetic heads 3Aand 3B are named odd-numbered tracks O₁, O₃, O₅, . . . , and tracks 4formed by the other of the magnetic heads 3A and 3B are namedeven-numbered tracks E₂, E₄, E₆, . . . , DV data of one frame isseparately recorded into a total of 10 tracks 4 formed of fiveodd-numbered tracks O₁, O₃, . . . and five even-numbered tracks E₂, E₄,. . . in the NTSC system and separately recorded into a total of 12tracks 4 formed of six odd-numbered tracks O₁, O₃, . . . and sixeven-numbered tracks E₂, E₄, . . . in the PAL system.

FIG. 2 shows a data format in each track 4 in the DV method. Each track4 is provided with, sequentially from a head entering side, an insertand track information (ITI) area Ar₁, an inter-block gap (IBG), an audiodata area Ar₂, an IBG, a video data area Ar₃, an IBG, a sub-code dataarea Ar₄, and an extension area Ar₅ as clearly shown in FIG. 2.

The ITI area Ar₁, stores various types of information related to tracks,such as pilot-frame data described later. The audio data area Ar₂ andthe video data area Ar₃ store audio data and video data, respectively.The sub-code data area Ar₄ stores sub codes. The extension area Ar₅ andthe IBGs record no data.

In the DV method, two adjacent tracks 4 are paired from the top of aframe sequentially. Data indicating a sequential number (hereinaftercalled a track-pair number) assigned to each pair and starting from zeroin a frame is stored in the audio data area Ar₂ and the video data areaAr₃.

Therefore, in the NTSC system, data indicating a track-pair number isrecorded into each track 4 from the top track 4 of a frame in the orderof “0,” “0,” “1,” “1,” . . . “5,” and “5.” In the PAL system, dataindicating a track-pair number is recorded into each track 4 from thetop track 4 of a frame in the order of “0,” “0,” “1,” “1,” . . . “6,”and “6.”

Therefore, it is easily recognized that reproduced DV data has beenrecorded into which track 4 in a frame, according to the track-pairnumber.

On the other hand, in the digital 8-mm method, to which the presentinvention is applied, a rotating drum 6 having the same diameter (40 mm)as in the Analog 8-mm method is rotated in a direction indicated by “a₂”at a rotating speed of 4500/1.001 rpm in the NTSC system and of 4500 rmpin the PAL system against 8-mm tape 5 to record video and audio signals(DV data) conforming to the DV-method data format, as shown in FIG. 3.

Also in this case, two magnetic heads 7A and 7B having different azimuthangles are mounted at positions 180 degrees apart on the rotating drum6. Therefore, the two magnetic heads 7A and 7B alternately scan the 8-mmtape 5 which runs in a direction indicated by “b₂” at a predeterminedangle. As a result, tracks 8 are sequentially formed at angles in thelongitudinal direction of the 8-mm tape 5 as shown in FIG. 3.

In the digital 8-mm method, DV data of two tracks in the DV method iscontinuously stored in one track 8 as a data pattern in the DV method.Specifically, in the digital 8-mm method, data in odd-numbered tracksO₁, O₃, O₅, . . . and data in even-numbered tracks E₂, E₄, E₆, . . . inthe DV method are paired and paired data is recorded into one track 8without changing the data contents.

More specifically, in the digital 8-mm method, data in the odd-numberedtrack O₁ and data in the even-numbered track E₂ in the DV method arecontinuously recorded into one track 8. Into the next track 8, data inthe odd-numbered track O₃ and data in the even-numbered track E₄ in theDV method are continuously recorded. In the same way, data in twoadjacent tracks in the DV method are paired and continuously recordedinto one track 8.

Therefore, in the digital 8-mm method, video and sound data of one frameis separately recorded into five tracks 8 on 8-mm tape in the NTSCsystem, and is separately recorded into six tracks 8 in the PAL system.

As described above, since data of two tracks in the DV method iscontinuously recorded into one track 8 on the 8-mm tape 5 with theDV-method data format in the digital 8-mm method, the area of the tapeis effectively used and high-quality video and sound can be recorded andreproduced for a long period of time.

(2) Automatic Track Finding (ATF) Format in the Digital 8-mm Method

An ATF format used in the digital 8-mm method will be described below.

In the DV method, one extra bit is inserted to every 24 bits (threebytes) for all data to be recorded to perform 24-25 conversion. Withthis operation, pilot signals having three frequencies are recorded intothe entire tracks 4 (FIG. 1) for ATF.

Specifically, as shown in FIG. 4A and FIG. 5A, in either of the NTSCsystem and the PAL system, a pilot signal having a frequency f0 isrecorded into odd-numbered tracks O₁, O₃, . . . , and pilot signalshaving frequencies f1 and f2 are alternately recorded into even-numberedtracks E₂, E₄, . . . . Therefore, into the entire tracks 4, pilotsignals are repeatedly recorded in the order of those having frequenciesf0, f1, f0, and f2.

As a result, in the DV method, when the magnetic head 3A scans a track 4(an odd-numbered track) in which the pilot signal having the frequencyf0 is recorded, during reproduction, the pilot signals having thefrequencies f1 and f2 are reproduced as cross-talk signals from adjacentboth-side tracks (even-numbered tracks). Therefore, when tracking iscontrolled such that the levels of the pilot signals having thefrequencies f1 and f2 are the same, stable tracking is obtained.

In the DV method, an ATF pattern is f0, f1, f0, and f2, or f0, f2, f0,and f1 from the top of a frame in the NTSC method as clearly shown inFIG. 4A, and an ATF pattern is always f0, f1, f0, and f2 from the top ofa frame in the PAL system as clearly shown in FIG. 5A.

It is specified in the DV method that one-bit control data called apilot frame, indicating the order of the frequencies of pilot signals ina frame, is stored at a predetermined position in the ITI area Ar₁ (FIG.2) of each track 4. It is also specified that the pilot-frame data isset to “0” when the ATF pattern is f0, f1, f0, and f2 from the top of aframe, and is set to “1” when the ATF pattern is f0, f2, f0, and f1.

Therefore, in the DV method, the pilot-frame data alternately changesbetween “0” and “1” in every frame in the NTSC system as shown in FIG.4A, and the pilot-frame data is always “0” in the PAL system as shown inFIG. 5A.

On the other hand, in the digital 8-mm method, since DV data of twotracks in the DV method is continuously recorded into 8-mm tape to formone track 8 as described above, if the above-described ATF format forthe DV method is applied as is, the frequency of the pilot signal is f0at the first half of a track 8 and it is f1 or f2 at the second half ofthe track 8. Tracking control based on pilot signals cannot beimplemented in this condition.

Therefore, in the present embodiment, pilot signals are recorded intotracks 8, one for each track 8 of the digital 8-mm method, so as to havefrequencies of f0, f1, f0, and f2 repeatedly in this order as an ATFformat in the digital 8mm method as shown in FIG. 4B and FIG. 5B.

When such an ATF format is employed in the digital 8-mm method, an ATFpattern from the top of a frame is f0, f1, f0, f2,. . . or f0, f2, f0,f1, . . . in the PAL system as shown in FIG. 5B, whereas an ATF patternfrom the top of a frame is f1, f0, f2, f0, . . . or f2, f0, f1, f0, . .. , in addition to f0, f1, f0, f2, . . . or f0, f2, f0, f1, . . . in theNTSC system. For such ATF patterns, pilot-frame data is not specified inthe DV method.

Therefore, in the present embodiment, the pilot-frame data is recordedsuch that it is set to “0” when the ATF pattern from the top of a frameis f0, f1, f0, f2, . . . or f1, f0, f2, f0, . . . , and is set to “1”when the ATF pattern is f0, f2, f0, f1, . . . or f2, f0, f1, f0.

As a result, the pilot-frame data alternately changes between “0” and“1” every two frames in the NTSC system as shown in FIG. 4B, and thepilot-frame data alternately changes between “0” and “1” every frame inthe PAL system as shown in FIG. 5B.

When the pilot-frame data is recorded in the way described above in thedigital 8-mm method, the frequencies of pilot signals to be used for thenext scene are easily determined.

FIG. 6 shows the relationship between the frequencies of pilot signalsand pilot-frame data in the NTSC system when the pilot-frame data isrecorded as described above in the digital 8-mm method, and FIG. 7 showsthe corresponding relationship in the PAL system.

In each of FIGS. 6 and 7, (A) indicates switching pulses SWP duringrecording and reproduction, and (B) indicates an ATF pattern in thedigital 8-mm method. Numbers (0 to 9 for the NTSC system, and 0 to 9, A,and B for the PAL system) shown below the frequencies in (B) indicateconsecutive numbers (hereinafter called DV-track numbers) assigned forconvenience from the top of a frame to DV data of one track in the DVmethod, recorded into tracks 8 in the digital 8-mm method.

In each of FIGS. 6 and 7, (C) indicates a rectangular-shaped signal(hereinafter called a first pilot-frame signal) showing pilot-frame datarecorded as described above in the digital 8-mm method by logicallevels, and (D) indicates a rectangular-shaped signal (hereinaftercalled a second pilot-frame signal) showing track-frame data assigned toDV data having each DV track number in the DV system, by logical levels.

The DV track numbers can be generated according to the track-pairnumbers described above, included in DV data in the tracks 8 in thedigital 8-mm method. The DV pilot-frame data can be detected accordingto the logical level of the switching pulse corresponding to a DV tracknumber.

It is understood clearly from FIGS. 6 and 7 that the frequency of apilot signal is uniquely determined according to the DV track number andthe logical levels of the first and second pilot-frame signals in eitherof the NTSC system and the PAL system when the ATF pattern correctlyrepeats f0, f1, f0, and f2.

Therefore, in the digital 8-mm method, when the pilot-frame data isrecorded as described above, a DV track number and the first and secondpilot-frame signals are generated according to the track-pair number andthe pilot-frame data included in DV data for video and sound(hereinafter called previous video and sound) which has been recordedinto 8-mm tape, for the next scene. The frequency of a pilot signal tobe superposed on each track 8 for video and sound (hereinafter callednext-scene video and sound) to be recorded on the 8-mm tape for the nextscene is easily determined such that the ATF pattern repeats f0, f1, f0,and f2 against the ATF pattern of the previous video and sound accordingto the generated DV track number of the generated first and secondpilot-frame signals.

When the pilot signal having the frequency determined in this way issequentially superposed on each track 8 for the next-scene video andsound in the digital 8-mm method, tracking loss is prevented duringreproduction at the boundary of the previous video and sound and thenext-scene video and sound. Therefore, high-quality video and sound arereproduced with tracking always being maintained.

(3) Structure of a Digital Video Camera According to the PresentEmbodiment

FIG. 8 shows a digital video camera according to the present embodiment.Two magnetic heads 12A and 12B having different azimuth angles aremounted on a rotating drum 11 at positions 180 degrees apart. With thesetwo magnetic heads 12A and 12B, video and audio signals are recordedinto or reproduced from 8-mm tape 13 by the digital 8-mm method.

In this digital video camera 10, when an input section 14 is operated toselect a recording mode, a control section 15 controls a drum motor 16and a capstan motor 17 such that the rotating drum 11 rotates at apredetermined rotating speed and the 8-mm tape 13 loaded so as to windaround the rotating drum 11 by a predetermined angle moves at apredetermined speed.

A pickup section 18 formed of a lens system and a charge coupled device(CCD) converts the optical image of an object to an electric signal andsends an obtained video signal S1 having an analog waveform to a signalprocessing section 19. The signal processing section 19 also receives anaudio signal S2 having an analog waveform from a microphone not shown.

Under the control of the control section 15, the signal processingsection 19 sequentially applies predetermined signal recordingprocessing corresponding to the DV method, such as digital conversionprocessing, encoding processing, multiplexing processing,error-correcting processing, 24/25 conversion processing (namely,pilot-signal adding processing), modulation processing, and processingfor adding control data indicating a track-pair number and pilot-framedata, to the video signal S1 and to the audio signal S2, andsequentially sends obtained DV data D1 to a head driver 20.

The head driver 20 sends the DV data Dl to the magnetic heads 12A and12B in units of two tracks in the DV method at timing when the magneticheads 12A and 12B scan the 8-mm tape 13, according to switching pulsesSWP given from the control section 15.

A flying erase head 12C having a head width of two tracks in the digital8-mm method is mounted at the middle of the two magnetic heads 12A and12B on the rotating drum 11, and receives a deletion signal S3 from thecontrol section 15.

As a result, in the digital video camera 10, when DV data D1 has beenrecorded on the 8-mm tape 13 by the digital 8-mm method, the DV data D1is deleted in units of two tracks in the digital 8-mm method by theflying erase head 12C and DV data D1 of two tracks in the DV method iscontinuously recorded into one track 8 (FIG. 3) on the 8-mm tape 13 bythe magnetic heads 12A and 12B.

In the digital video camera 10, the video signal S1 output from thepickup section 18 and the audio signal S2 output from the microphone arerecorded on the 8-mm tape 13 by the digital 8-mm method during therecording mode in this way.

When the input section 14 is operated to select a reproduction mode, thecontrol section 15 controls the drum motor 16 and the capstan motor 17such that the rotating drum 11 rotates at the same predeterminedrotating speed as in the recording mode and the 8-mm tape 13 loaded soas to wind around the rotating drum 11 by the predetermined angle movesat the same predetermined speed as in the recording mode.

As a result, every time the rotating drum 11 rotates by one turn, DVdata D1 of one track in the digital 8-mm method (corresponding to twotracks in the DV method) is sequentially reproduced by the magneticheads 12A and 12B, and is sent to the signal processing section 19through the head driver 20.

Under the control of the control section 15, the signal processingsection 19 outputs the received DV data D1 to the outside through aDV-data output terminal 21A, applies predetermined signal reproductionprocessing corresponding to the DV method, such as demodulationprocessing, error-correcting processing, processing for separating videodata and audio data, decoding processing of the video data and the audiodata, and analog conversion processing of the video data and the analogdata, to the DV data D1 received through the head driver 20, and alsooutputs an obtained video signal S4 and an obtained audio signal S5 bothhaving analog waveforms to the outside through a video output terminal21B and an audio output terminal 21C.

The signal processing section 19 also extracts a pilot signal added tothe DV data D1 and sends it to the control section 15. The controlsection then control the rotating speed of the capstan motor 17according to the pilot signal to perform tracking control.

In this way, the DV data D1 recorded on the 8-mm tape 13 by the digital8-mm method is reproduced and output to the outside during thereproduction mode in the digital video camera 10.

(4) Detailed Processing in the Control Section

The control section 15 rotates the rotating drum 11 at a predeterminedspeed and moves the 8-mm tape 13 at a predetermined speed during therecording mode as described above. As a result, when video and audio DVdata D1 has been recorded on the 8-mm tape 13 as in taking the nextscene, the DV data D1 is reproduced by the magnetic heads 12A and 12Band sent to the signal processing section 19 through the head driver 20.

The signal processing section 19 enters the reproduction mode for ashort period of time under the control of the control section 15. Whenthe signal processing section 19 receives the DV data D1 through thehead driver 20, for example, it detects a track-pair number andpilot-frame data included in the DV data D1 and sends a detection resultto the control section 15 as a control-information detection signal S6.

When the control section 15 receives the control-information detectionsignal S6, which includes a track-pair number, from the signalprocessing section 19, it generates the DV track numbers (0 to 9 in theNTSC system as shown by (B) in FIG. 9, and 0 to 9, A, and B in the PALsystem as shown by (B) in FIG. 10) of the corresponding track 8according to the track-pair number, and then continuously generates twoDV track numbers at a constant interval every time the switching pulsesSWP are inverted.

In the digital video camera 10, a track-pair number included inreproduced DV data D1 is detected by the signal processing section 19,and then sent to the control section 15 at timing when the switchingpulses SWP are inverted next.

Therefore, DV track numbers are generated with a delay of half theperiod of the switching pulses SWP after a track-pair number is actuallydetected, in the control section 15. Consequently, when a DV tracknumber of “8” in the NTSC system ((B) in FIG. 9) or “A” in the PALsystem ((B) in FIG. 10) is generated in the control section 15, thereproduction of the top track 8 of the next frame is actually started,or the generation of a new track 8 is actually started for taking thenext scene.

In addition to the above generation processing of DV track numbers, thecontrol section 15 generates the above-described first pilot-framesignal S7A (shown by (C) in FIG. 9) or S7B (shown by (C) in FIG. 10)which has the pilot frame data given from the signal processing section19 as an initial value, according to the pilot-frame data included inthe control-information detection signal S6 sent from the signalprocessing section 19, a DV track number, and the logical level of theswitching pulses SWP.

Specifically, the control section 15 generates the first pilot-framesignal S7A so as to invert its logical level when the DV track numbergenerated inside is “6” and the logical level of the switching pulsesSWP is “0” in the NTSC system as shown by (A) to (C) in FIG. 9; andgenerates the first pilot-frame signal S7B so as to invert its logicallevel when the DV track number generated inside is “8” in the PAL systemas shown by (A) to (C) in FIG. 10, with a communication delay, describedlater, generated when the first pilot-frame signal S7A or S7B is sent tothe signal processing section 19 being taken into account.

The control section 15 also generates the above-described pilot-framesignal S8A (shown by (E) in FIG. 9) or S8B (shown by (E) in FIG. 10)according to the logical level of the switching pulses SWP and a DVtrack number.

Specifically, in synchronization with the first pilot-frame signal, thecontrol section 15 generates the second pilot-frame signal S8A so thatit rises when the DV track number generated inside is “6” and thelogical level of the switching pulses SWP is “1” and it falls when theDV track number is “6” and the logical level of the switching pulses SWPis “0” in the NTSC system as shown by (A), (B), and (E) in FIG. 9; andgenerates the second pilot-frame signal S8B always having a logicallevel of “0” in the PAL system as shown by (E) in FIG. 10.

The control section 15 sends the deletion signal S3 (FIG. 8) to theflying erase head 12C (FIG. 8) at timing when the first pilot-framesignal S7A or S7B obtained in the foregoing way changes its logicallevel, and at the same time has the signal processing section 19 startsignal recording processing to start a recording operation.

The control section 15 sequentially determines the frequency (shown in(G) of FIG. 9 and (F) of FIG. 10) of a pilot signal to be recorded ineach track 8 to be newly formed on the 8-mm tape 13 by a recordingoperation such that an ATF pattern of f0, f1, f0, and f2 continues evenat the boundary of previous video and sound and next-scene video andsound, according to the DV track number, and the logical levels of thefirst pilot-frame signal S7A or S7B and the second pilot-frame signalS8A or S8B, and sends a determination result to the signal processingsection 19 as a frequency determination signal S9. As a result,according to this frequency determination signal S9, the signalprocessing section 19 applies 24/25 conversion processing as describedabove. DV data to which the pilot signal having the frequency determinedby the control section 15 has been attached is thus generated and isrecorded on the 8-mm tape 13 (shown by (H) in FIG. 9 and (G) in FIG.10).

The control section 15 further sends the first pilot-frame signal S7A orS7B to the signal processing section 19. In the signal processingsection 19, after the pilot frame data obtained according to the firstpilot-frame signal S7A or S7B is stored at a predetermined position inthe corresponding DV data, the DV data is recorded on the 8-mm tape(shown by (D) in FIG. 9 and (D) in FIG. 10).

When new 8-mm tape 13 is used during the recording mode, for example, DVdata is not reproduced from the 8-mm tape 13 at an early stage of therecording mode, and therefore, the signal processing section 19 does notsend the control-information detection signal S6, which includes atrack-pair number and pilot frame data, to the control section 15.

In this case, the control section 15 sequentially generates theabove-described DV track numbers by itself according to the switchingpulses SWP, and also generates the first pilot-frame signal S7A or S7Band the second pilot-frame signal S8A or S8B according to the generatedDV track numbers and the logical levels of the switching pulses SWP.

The control section 15 executes the same processing as for the nextscene described above according to the DV track number, the firstpilot-frame signal S7A or S7B and the second pilot-frame signal S8A orS8B to store pilot frame data which has its value inverted at aninterval of two frames in the NTSC system or of one frame in the PALsystem, in DV data, and records the DV data on the 8-mm tape 13 while apilot signal having a predetermined frequency is superposed thereon sothat an ATF pattern of f0, f1, f0, and f2 continues even at the boundaryof previous video and sound and next-scene video and sound.

When the DV data is recorded on the 8-mm tape in this way, if DV datareproduced from the 8-mm tape 13 is output to the outside as is,pilot-frame data included in each DV data does not conform to the DVmethod and compatibility cannot be obtained with units conforming to theDV method.

Therefore, the control section 15 generates the second pilot-framesignal S8A or S8B according to a track-pair number included in thecontrol-information detection signal S6 sent from the signal processingsection 19, and sends it to the signal processing section 19 during thereproduction mode in the same way as in the recording mode.

The signal processing section 19 changes the pilot-frame data ofreproduced DV data to the logical level of the second pilot-frame signalS8A or S8B sent from the control section 15, and outputs the DV data tothe outside through the DV-data output terminal 21A.

As described above, the digital video camera 10 can output DV dataconforming to the DV method as reproduced DV data, and maintainscompatibility with other units.

(5) Operation and Effect in the Present Embodiment

With the above structure, the digital video camera 10 records DV datahaving the data format of the DV method in one track on the 8-mm tape 13by the magnetic heads 12A and 12B, mounted on the rotating drum 11, inunits of two tracks in the DV method during the recording mode.

Since the digital video camera 10 records data of two tracks in the DVmethod continuously in one track on 8-mm tape, which is wider than DVtape, a tape area is effectively used and high-quality video and audiosignals can be recorded for a long period of time.

In addition, in this case, since pilot-frame data included in DV data isinverted at an interval of two frames in the NTSC system or of one framein the PAL system in the digital video camera 10, the determination ofthe frequency of a pilot signal to be recorded into each track of videoand audio signals for the next scene such that tracking is maintainedeven at the boundary of previous video and sound and next-scene videoand sound during reproduction is simplified according to pilot-framedata included in each DV data of previous video and sound duringrecording of the next scene.

Since the determination of the frequency of a pilot signal to berecorded into each track of next-scene video and sound is simplified inthis way, the corresponding circuit structure and program are alsosimplified.

With the above structure, since DV data having the data format of the DVmethod is recorded in one track on 8-mm tape in units of two tracks inthe DV method during the recording mode, a tape area is effectively usedand a digital video camera which can record video and audio signals fora long period of time with high quality is implemented. In this case,since pilot-frame data included in DV data is inverted at an interval oftwo frames, the determination of the frequency of a pilot signal to berecorded into each track for the next scene is simplified, andtherefore, a digital video camera which can simplify the correspondingcircuit structure and program is implemented.

(6) Modifications

In the above embodiment, the present invention is applied to a digitalvideo camera. The present invention can also be applied to units otherthan a digital video camera, such as installation-type digital videotape recorders.

In the above embodiment, the signal processing section 19 has thefunctions of recording-data generation means for generating recordingdata having the data format of the DV method, of control-data extractingmeans for extracting pilot-frame data formed of one-bit control datafrom DV data D1 reproduced from the 8-mm tape 13, and of control-datachanging means for changing pilot-frame data included in DV data D1reproduced from the 8-mm tape 13 to a value corresponding to the DVmethod during reproduction. In addition to this case, the presentinvention can also be applied to a case in which the functions of therecording-data generation means and the control-data extracting meansare implemented by a signal processing circuit in a usual video cameraconforming to the DV method, and the control section 15 has the functionof the control-data changing means.

In the above embodiment, the present invention is applied to the digitalvideo camera 10, which records recording data having the data format ofthe DV method on the 8-mm tape 13. In addition to this case, the presentinvention can also be applied to magnetic recording apparatuses andmagnetic recording and reproduction apparatuses which record recordingdata having the data format of a digital recording method other than theDV method on magnetic tape other than that 8 mm wide.

In this case, recording-data generation means for generating recordingdata, recording means (the head driver 20, the rotating drum 11, themagnetic heads 12A and 12B, and the flying erase head 12C in the aboveembodiment) for recording recording data on magnetic tape, andreproduction means (the same as the recording means in the aboveembodiment) for reproducing recording data recorded on the magnetic tapeneed to be configured correspondingly to a digital recording methodused.

What is claimed is:
 1. A magnetic recording apparatus comprising:recording-data generation means for applying predetermined signalprocessing which includes processing for adding a pilot signal fortracking control, to a video signal to generate recording data having adata format corresponding to a predetermined digital recording method;and recording means for sequentially recording the recording datagenerated by the recording-data generation means, of two tracks in thedigital recording method continuously in one track on magnetic tape,wherein the recording-data generation means places in the recording dataone-bit control data indicating the arrangement of the frequencies ofpilot signals in tracks on the magnetic tape, the one-bit control databeing inverted at an interval of two frames in the NTSC system and ofone frame in the PAL system.
 2. A magnetic recording apparatus accordingto claim 1, wherein the Digital Video method is used as the digitalrecording method, and the magnetic tape has a tape width conforming tothe Analog 8-mm method.
 3. A magnetic recording method comprising: afirst step for applying predetermined signal processing which includesprocessing for adding a pilot signal for tracking control, to a videosignal to generate recording data having a data format corresponding toa predetermined digital recording method; and a second step forsequentially recording the generated recording data of two tracks in thedigital recording method continuously in one track on magnetic tape,wherein, in the first step, one-bit control data indicating thearrangement of the frequencies of pilot signals in tracks on themagnetic tape, the one-bit control data being inverted at an interval oftwo frames in the NTSC system and of one frame in the PAL system, isplaced in the recording data.
 4. A magnetic recording method accordingto claim 3, wherein the Digital Video method is used as the digitalrecording method, and the magnetic tape has a tape width conforming tothe Analog 8-mm method.
 5. A magnetic recording and reproductionapparatus comprising: recording-data generation means for applyingpredetermined signal recording processing which includes processing foradding a pilot signal for tracking control, to a video signal togenerate recording data having a data format corresponding to apredetermined digital recording method; and recording means forsequentially recording the recording data generated by therecording-data generation means, of two tracks in the digital recordingmethod continuously in one track on magnetic tape, wherein therecording-data generation means places in the recording data one-bitcontrol data indicating the arrangement of the frequencies of pilotsignals in tracks on the magnetic tape, the one-bit control data beinginverted at an interval of two frames in the NTSC system and of oneframe in the PAL system.
 6. A magnetic recording and reproductionapparatus according to claim 5, wherein the Digital Video method is usedas the digital recording method, and the magnetic tape has a tape widthconforming to the Analog 8-mm method.
 7. A magnetic recording andreproduction apparatus according to claim 5, further comprising:reproduction means for reproducing the recording data recorded on themagnetic tape; control-data extracting means for extracting the controldata from the recording data reproduced by the reproduction means; andcontrol means, wherein the control means has the reproduction meansreproduce the recording data which has been formed in tracks on themagnetic tape; the control means has the control-data extracting meansextract the control data from the reproduced recording data; when therecording data based on the video data is recorded, the control meanssequentially determines the frequencies of pilot signals to besuperposed on the recording data based on the video signal, according tothe extracted control data such that the arrangement of the frequenciesof the pilot signals which have been recorded in tracks on the magnetictape is followed by a predetermined pattern; and the control meanscontrols the recording-data generation means such that the pilot signalshaving the determined frequencies are added to generate the recordingdata based on the video signal.
 8. A magnetic recording and reproductionapparatus according to claim 5, further comprising control-data changingmeans for changing the control data included in the recording datareproduced from the magnetic tape by the reproduction means to a valuecorresponding to the digital recording method and for outputting it tothe outside.
 9. A magnetic recording and reproduction method comprising:a first step for applying predetermined signal recording processingwhich includes processing for adding a pilot signal for trackingcontrol, to a video signal to generate recording data having a dataformat corresponding to a predetermined digital recording method; and asecond step for sequentially recording the generated recording data oftwo tracks in the digital recording method continuously in one track onmagnetic tape, wherein, in the first step, one-bit control dataindicating the arrangement of the frequencies of pilot signals in trackson the magnetic tape, the one-bit control data being inverted at aninterval of two frames in the NTSC system and of one frame in the PALsystem, is placed in the recording data.
 10. A magnetic recording andreproduction method according to claim 9, wherein the Digital Videomethod is used as the digital recording method, and the magnetic tapehas a tape width conforming to the Analog 8-mm method.
 11. A magneticrecording and reproduction method according to claim 9, wherein, in thefirst step, the recording data which has been formed in tracks on themagnetic tape is reproduced; the control data is extracted from thereproduced recording data; the frequencies of pilot signals to be addedto the recording data based on the video signal are sequentiallydetermined according to the extracted control data such that thearrangement of the frequencies of the pilot signals which have beenrecorded in tracks on the magnetic tape is followed by a predeterminedpattern; and the pilot signals having the determined frequencies areadded to generate the recording data based on the video signal.
 12. Amagnetic recording and reproduction method according to claim 9, furthercomprising: a third step for reproducing the recording data based on thevideo signal from the magnetic tape; and a fourth step for changing thecontrol data included in the reproduced recording data to a valuecorresponding to the digital recording method and for outputting it tothe outside.